Go to the Texas Hold 'em Tournament table at the first casino and join a game. You will have the ability to go all in. there will be a 75% chance of getting a good hand, so go all in. Most other players will call and go all in. You will most likely win and get cash around 20,000 dollars.
Hold the Right Shoulder button down, and walk in and out of the southern-most casino's loading point and walk back and forth.
You can unlock all casinos without having to play thru tournaments. At "TOUCH SCREEN TO START", press Y, X, Y, B, L, R, then control pad. Left for the Amazon, right for the Nebula, down for everything up to Renaissance. If done correctly, you should hear chips.